A recent meta-analysis reported benefits of adjuvant bisphosphonate treatment in postmenopausal women with early-stage breast cancer, including improved survival and reduced recurrences in the bone. SUCCESS A trial researchers compared two and five years of zoledronate treatment following adjuvant chemotherapy to assess benefits between durations.

A total of 3,754 women with high-risk, early-stage breast cancer were randomly assigned to adjuvant chemotherapy treatment with three cycles of combination 5-fluorouracil, epirubicin, and cyclophosphamide (FEC) followed by either three cycles of docetaxel or three cycles of gemcitabine plus docetaxel. After chemotherapy, patients were randomly assigned to five years of zoledronate treatment (4 mg IV every three months for two years, followed by 4 mg IV every six months for three years) versus two years of zoledronate treatment (4 mg IV every three months for two years). Outcomes were DFS and OS, with survival times measured between two and four years after zoledronate treatment began. Median observation time was 2.95 years for DFS and 3 years for OS.